Perfect location right opposite the BTS Skytrain at On Nut and Tesco Lotus. The Rhythm building is about 3 years old, good pool, gym, and other facilities on the 37th floor. Maintained corridors very clean on a daily basis. Typically good Thai standards.
Khun Piyakorn's condo is a suitable size for two people staying for a while. We had our 4 year old with us and the extra bed was a thin mattress, not really suitable, so we all squeezed into the main bed.
Everything works well and it does give you a homely feel.
We did have cleanliness issues in the bathroom and kitchen upon arrival and would expect a much better standard for THB1800/night, however, Khun Piyakorn did come over the next day to sort out the main issues.
Overall a great stay and I'd be happy to stay again. Don't forget your key card otherwise security won't let you out of the building while they don't have a door release button fitted yet.